Self-propelling jet nozzles for sewer pipe cleaning apparatus are disclosed, for example, in the Roland E. Shaddock U.S. Pat. No. 3,658,589, issued Apr. 25, 1972. These prior known nozzles have one piece hollow heads with a ring of rearwardly opening circumferentially spaced nozzle holes of constant diameter throughout their length so that the propelling jet streams do not converge to increase in velocity as they pass through the holes and soon erode and enlarge the holes to decrease the propelling force of the jets.
It would therefore be an improvement in this art to provide a method of making self-propelled jet nozzles for sewer pipe cleaning and the like that permits the formation of circumferentially spaced nozzle bores that have inner ends larger than outer ends and effective to wedge lock wear resistant nozzle tubes in the bores under the action of the high pressure streams of water flowing through the bores.